Requirements:- Dopus 12 (for the custom Standalone Image Viewer buttons)- Some kind of video thumbnail indexer (I'll be using Video Thumbnail Maker and my buttons will reflect that. Adjust for your needs. NOTE: Using Video Thumbnail Maker, I found I needed to use the full path to the saved profile in order to work correctly)

I made a script button to open the preview/index of a selected video file. It is a bit more complex than your "View Thumbnail" button. My script checks if there is a VTX file and opens it by default, otherwise it checks if there is a JPG file and opens it.